U.S. Pat. No. 3,800,632 pertains to a clamping device for the exact manual resharpening of knife blades on a whetstone, in which the knife blade is mounted in the clamping device and at least one support contour of the clamping device is designed such that it is congruent with the contour of the cutting edge of the knife blade or that it extends equidistantly from the contour of the cutting edge of the knife blade. However, according to the disclosure content of the document, the constant distance between the support contour and the contour of the cutting edge of the knife blade is not given over the entire length of the knife blade, but in some sections only.
The drawback of this embodiment is consequently that the sharpening of the cutting edge of the knife blade up to the tip of the knife is difficult to carry out and the result of sharpening is thus qualitatively unsatisfactory and is not constant.
A highly complicated embodiment of a clamping device for the exact manual resharpening of knife blades on a whetstone is disclosed in DE 7,418,952 U1, in which the knife blade is held in a frame and is guided with this frame over the sharpening surface. Rollers are provided to support the movement. This clamping device is suitable for sharpening straight blades only.
U.S. Pat. No. 6,030,281 shows a highly complicated embodiment of a clamping device for the exact manual resharpening of knife blades on a whetstone. This device is likewise suitable for straight blades only.